I agree that Kennedy's 1980 primary campaign sucked, but that was the one thing Carter's Georgians were good at. Both in 1976 (where I'd actually give even odds in a Carter Vs. Kennedy match-up) and in 1980 they performed brilliantly. But in both the 1976 & 1980 general elections the Carter general election team was horrible against fantastic Republican teams.
I agree that Kennedy might well have ran in 1972, but on the other hand he turned down a sure thing to be the nominee in 1968[1] and it's entirely possible he chooses not to run in 1972 (do note that it wasn't a Republican year so much as an anti-McGovern year. Pre-dirty tricks Muskie was ahead of Nixon in the polls, and Congressionally the Republicans didn't do that well.)
So assuming he waits until 1976 he is certainly better prepared than 1980. For one he isn't running against the establishment, he is the establishment. For two, articulating that Carter was incompetent at running a government but that you have the same policies except a little left[2] is far harder than articulating the Democratic position against the Republican position.
Kennedy's main problem in 1976 is that the public liked the anti-Washington image (Reagan, Carter) and not so much the insider (Ford) but keep in mind Ford made back a 30 point deficit and given a couple more days might well have beaten Carter.
I'm willing to bet that Iowa is key. Carter (well, Hamilton Jordon) grasped that when no one else did. So let's have some young hotshot Democratic who works for Kennedy also get that. The other problem is money, as 1976 brought in all kinds of new post-Watergate rules.
However it's possible (though not probable) that Kennedy wins the nomination. No problem with that.
The problem lies in the South (as Tgibbs is on about) and with Ford—who, after all, has most of the smart Republican political operative corps working for him…*and Republicans, for historical reasons[3], had generally better political consultants.
We have a few good people around. For speechwriting we have the old Kennedy forces (Sorensen, Schlesinger) + Bob Shrum (yes, a horrible strategist but a darn good speechwriter) plus the old RFK Presidential run guys who are a lot more in touch in '76 than 1980.
So at the least Kennedy's general election time should be a fair bit better than Carters, if still not as good as Fords.
There are 31 close states (7.6% at the outside). Carter has 297 electoral votes. Let's take away the whole south including Missouri: 297 – 139 = 158.
Oregon (0.8%), Maine (0.8%) and Iowa (1.0%) can all be flipped to Kennedy which takes us up to 176. Add Illinois (2.2%), Washington (3.9%), New Jersey (2.2%), New Mexico (2.4%), California (1.7%), and Connecticut (5.2%).
That takes us to 285, which leaves us a few EV to spare.
[1] Outside the realm of this thread, but EMK was offered by Mayor Daley and the bosses along with the anti-war and McCarthy forces the chance to go against Humphrey. EMK + McCarthy would have stalled Humphrey on the first ballot, and I'd wager that Kennedy would have taken Humphrey on the second.
[2] No, WCDouglas Kennedy was not far-left—he might have wanted socialized healthcare, but Nixon offered him national health insurance. The entire US political spectrum was well to the left back than, Nixon today (for instance) would be a Democrat with left-wing social programs and centrist on foreign policy while Ford could be a centrist Democrat or one of the last (in today's terms) liberal Republicans.
Kennedy of '76 would today be out on the left wing, probably the farthest left, but back then he was solidly in the fairly populous left-liberal New Democratic wing.
[3] Lots of footnotes, huh? Anyway it centred on the Democratic Solid South, the need to take 2/3 of the Northern electoral votes to win, FDR & the New Deal making that impossible for a time, and finally the rise of conservative activists in the GOP. All of this meant far better grassroots organizing & political strategy than Democrats.